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Martinez-Calderon, C., Oonishi, T., Shiokawa, K. et al. Characteristics and longitudinal extent of VLF quasi-periodic emissions using multi-point ground-based observations. Earth Planets Space 75, 148 (2023).

Characteristics and longitudinal extent of VLF quasi-periodic emissions using multi-point ground-based observations

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Author: Martinez-Calderon, Claudia1; Oonishi, Tomoka1; Shiokawa, Kazuo1;
Organizations: 1Institute for Space-Earth Environmental Research, Nagoya, Japan
2Sodankylä Geophysical Observatory, Sodankylä, Finland
3ISTP, Russian Academy of Sciences, Irkutsk, Russia
4Kanazawa University, Kanazawa, Japan
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 8.4 MB)
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Language: English
Published: Springer Nature, 2023
Publish Date: 2023-10-18


Quasi-periodic (QP) emissions are a type of magnetospheric ELF/VLF waves characterized by a periodic intensity modulation ranging from tens of seconds to several minutes. Here, we present 63 QP events observed between January 2017 and December 2018. Initially detected at the VLF receiver in Kannuslehto, Finland (KAN, MLAT = 67.7°N, L = 5.5), we proceeded to check whether these events were simultaneously observed at other subauroral receivers. To do so we used the following PWING stations: Athabasca (ATH, MLAT = 61.2°N, L = 4.3, Canada), Gakona (GAK, MLAT = 63.6°N, L = 4.9, Alaska), Husafell (HUS, MLAT = 64.9°N, L = 5.6, Iceland), Istok (IST, MLAT = 60.6°N, L = 6.0, Russia), Kapuskasing (KAP, MLAT = 58.7°N, L = 3.8, Canada), Maimaga (MAM, MLAT = 58.0°N, L = 3.6, Russia), and Nain (NAI, MLAT = 65.8°N, L = 5.0, Canada). We found that: (1) QP emissions detected at KAN had a relatively longer observation time (1–10 h) than other stations, (2) 11.3% of the emissions at KAN were observed showing one-to-one correspondence at IST, and (3) no station other than IST simultaneously observed the same QP emission as KAN. Since KAN and IST are longitudinally separated by 60.6°, we estimate that the maximum meridional spread of conjugated QP emissions should be close to 60° or 4 MLT. Comparison with geomagnetic data shows half of the events are categorized as type II, while the rest are mixed (type I and II). This study is the first to clarify the longitudinal spread of QP waves observed on the ground by analyzing simultaneous observations over 2 years using multiple ground stations.

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Series: Earth, planets and space
ISSN: 1343-8832
ISSN-E: 1880-5981
ISSN-L: 1343-8832
Volume: 75
Issue: 1
Article number: 148
DOI: 10.1186/s40623-023-01898-1
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Funding: The research and data analysis made by CMC is funded by Nagoya University and several Grant-in-Aid for Scientific Research from Japan Society for the Promotion of Science (JSPS 16H06286 (PWING project), 21H04518, 21H04518, 22K21345 (PBASE program)).
Copyright information: © The Author(s) 2023. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit